Jul. 4, 2014

Sea lampreys are an invasive parasitic fish that attach themselves to other fish. / File photo

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Watchdog/enterprise reporter

PORT CLINTON — Although federal wildlife officials planned to search the Portage River last month for an invasive, parasitic fish, they ran out of time to complete their survey.

So they pushed back their efforts to look for sea lampreys to late this month or August, said Aaron Jubar, U.S. Fish and Wildlife Service team leader for sea lamprey larval assessment.

The researchers began shocking and treating other Lake Erie tributaries to produce the lampreys — one of the oldest invasive species on the Great Lakes — last month in New York and worked their way west, Jubar said.

Storms delayed some of the work, and researchers didn’t make it further west than northeast Ohio, he said.

Sea lampreys are native to the Atlantic Ocean and have a suction-cup mouth with teeth and a rasping tongue that they use to attach to fish and feed off of them. In the lamprey’s lifetime, it can kill an estimated 40 pounds of fish, according to the Great Lakes Fishery Commission.

The U.S. Fish and Wildlife Service is doing the work as part of its research to determine why sea lampreys, which came to the Great Lakes in 1921, have been increasing on Lake Erie during the past 10 years.

“They seem to be producing more larvae than they have in the past, and we’re not sure why,” Michael Twohey, supervisory fish biologist for USFWS in Marguette and Ludington, Mich., said last month.

“We are looking for that source of lampreys that has eluded us.”

Researchers were encouraged when they surveyed rivers in New York that they had treated last year with a chemical that kills the lampreys, called lampricide, and did not find the fish there, Jubar said.

That means the fish likely have not reestablished populations in those areas, he said.

Rain increased water levels on the Chagrin and Grand rivers in northeast Ohio, making surveying more difficult, Jubar said.